/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.aop.support;

import java.io.Serializable;

import org.springframework.lang.Nullable;

/**
 * Abstract superclass for expression pointcuts,
 * offering location and expression properties.
 *
 * @author Rod Johnson
 * @author Rob Harrop
 * @see #setLocation
 * @see #setExpression
 * @since 2.0
 */
@SuppressWarnings("serial")
public abstract class AbstractExpressionPointcut implements ExpressionPointcut, Serializable {

    @Nullable
    private String location;

    @Nullable
    private String expression;


    /**
     * Set the location for debugging.
     */
    public void setLocation(@Nullable String location) {
        this.location = location;
    }

    /**
     * Return location information about the pointcut expression
     * if available. This is useful in debugging.
     *
     * @return location information as a human-readable String,
     * or {@code null} if none is available
     */
    @Nullable
    public String getLocation() {
        return this.location;
    }

    public void setExpression(@Nullable String expression) {
        this.expression = expression;
        try {
            onSetExpression(expression);
        } catch (IllegalArgumentException ex) {
            // Fill in location information if possible.
            if (this.location != null) {
                throw new IllegalArgumentException("Invalid expression at location [" + this.location + "]: " + ex);
            } else {
                throw ex;
            }
        }
    }

    /**
     * Called when a new pointcut expression is set.
     * The expression should be parsed at this point if possible.
     * <p>This implementation is empty.
     *
     * @param expression expression to set
     * @throws IllegalArgumentException if the expression is invalid
     * @see #setExpression
     */
    protected void onSetExpression(@Nullable String expression) throws IllegalArgumentException {
    }

    /**
     * Return this pointcut's expression.
     */
    @Override
    @Nullable
    public String getExpression() {
        return this.expression;
    }

}
